The present invention relates to the field of radiation delivery systems, including photocuring systems.
The utilization of photopolymerized materials, adhesives and encapsulants in industrial manufacturing applications has increased dramatically in the past decade. For the most part, this has been a result of the advances in photochemistry.
Correspondingly, light source technology has evolved utilizing medium pressure linear ultraviolet (UV) lamps, microwave powered UV lamps, xenon lamps and high-pressure mercury vapour and metal halide lamps. These lamps provide photons in the absorption bandwidth of the photo-initiators utilized in the chemistry required to complete the photochemical reaction.
In general, the available old lamp technology required to provide the energizing photons operates with an efficiency of 1-10% in order to provide broadband energy between 248 nanometres (nm) to 500 nm in wavelength required for the photochemical reaction. Typically these lamps require a warm up time to reach full output power, cannot be turned off and on rapidly, generate a great deal of electromagnetic interference (EMI) necessitating extensive shielding, require venting for ozone produced and often contain mercury, an environmentally hazardous substance. Other commonly used light technologies have a limited lifetime (greater than 1,000 hours) with continuous degradation over time.
There is accordingly a need for apparatus which efficiently emits light energy suitable for initiating a photoreaction.
The present invention is directed towards a light curing device, which has common, but by no means exclusive application to industrial manufacturing applications involving photoreactive materials. When used herein, it should be understood that xe2x80x9ccuringxe2x80x9d, xe2x80x9cphotocuringxe2x80x9d and xe2x80x9cphotoreactionxe2x80x9d are intended to include the concepts of xe2x80x9cthermal curingxe2x80x9d, xe2x80x9cpolymerizingxe2x80x9d and xe2x80x9cphotoinitiatingxe2x80x9d, each of which terms (and variations thereof) may be used interchangeably herein.
The device according to the present invention includes a housing and a light emitting semiconductor array mounted to the housing, capable of emitting light energy having a light output wavelength suitable for initiating a photoreaction. The device also has a power source for providing power to energize the array to emit light energy and a controller coupled to the power source for varying the power provided by the power source to the array.
The invention is also directed towards the use of the present photocuring device invention described above to cure photoreactive materials. Similarly, the invention is directed towards a method of curing photoreactive products using the photocuring device invention. The method comprises the steps of:
A. providing a light curing device of the present invention;
B. positioning a photoreactive product proximate the light curing device; and
C. causing the device to emit light energy suitable for initiating a photoreaction onto the product until the product is sufficiently photocured.